Answer:
Q = 62 ( since we are instructed not to include the units in the answer)
Explanation:
Given that:



Q = ???
Now the gas expands at constant pressure until its volume doubles
i.e if 
Using Charles Law; since pressure is constant




mass of He =number of moles of He × molecular weight of He
mass of He = 3 kg × 4
mass of He = 12 kg
mass of Ar =number of moles of Ar × molecular weight of Ar
mass of He = 7 kg × 40
mass of He = 280 kg
Now; the amount of Heat Q transferred = 
From gas table

∴ Q = 
Q = 
Q = 62 MJ
Q = 62 ( since we are instructed not to include the units in the answer)
Answer:

Explanation:
Density is defined as mass ler unit volume, expressed as

Where m is mass,
is density and v is the volume. For a sphere, volume is given as

Replacing this into the formula of density then

Given diameter of 2.24 in then the radius is 1.12 in. Substituting 0.82 lb for m then

Answer:
5.6 mm
Explanation:
Given that:
A cylindrical tank is required to contain a:
Gage Pressure P = 560 kPa
Allowable normal stress
= 150 MPa = 150000 Kpa.
The inner diameter of the tank = 3 m
In a closed cylinder there exist both the circumferential stress and the longitudinal stress.
Circumferential stress 
Making thickness t the subject; we have


t = 0.0056 m
t = 5.6 mm
For longitudinal stress.



t = 0.0028 mm
t = 2.8 mm
From the above circumferential stress and longitudinal stress; the stress with the higher value will be considered ; which is circumferential stress and it's minimum value with the maximum thickness = 5.6 mm